This invention relates to a machine for automatically inspecting shaped, lined closures such as bottle caps and rejecting those which do not meet pre-established criteria for shape and seal. More particularly, it relates to a machine for automatically inspecting and rejecting closures having resilient sealing liners.
Proper inspection of bottle closures is a matter of considerable importance, both to the ultimate consumer and to bottlers. It is important to the consumer because defective closures can leak, permitting contamination of the contents and undesired escape thereof. It is important to the bottler for the same reasons and for the additional reason that defective closures can jam modern high speed bottling equipment.
While bottle caps are manufactured at high rates of speed using mass production techniques, they are typically inspected at rates of speed limited to the effective speed of human visualization and manual removal. Commercial lining machines, such as are described in U.S. Pat. Nos. 3,135,019 and 3,360,827, issued to Ernest O. Aichele, can provide plastic sealing linings to pre-formed bottle closure shells at rates of 1400 caps per minute. Consequently, most cap manufacturers inspect only a small percentage of the lined caps and statistically extrapolate these inspections to cover the entire production. This technique is time-consuming, subjective, and inherently unreliable.
Similarly, most bottlers also inspect only a small percentage of caps purchased. Typically, they inspect one box per shipment, and if the number of defects in that box exceeds their maximum, they reject the entire shipment.